Merge pull request #270 from Krinkle/runslist-cc

Set Cache-Control headers for runs list and runs view

src/Xhgui/Controller.php

@@ -36,7 +36,19 @@ public function templateVars()
 
     public function render()
     {
-        $this->app->render($this->_template, $this->_templateVars);
+        // We want to render the specified Twig template to the output buffer.
+        // The simplest way to do that is Slim::render, but that is not allowed
+        // in middleware, because it uses Slim\View::display which prints
+        // directly to the native PHP output buffer.
+        // Doing that is problematic, because the HTTP readers set via $app->response()
+        // must be output first, which won't happen until after the middleware
+        // is completed. Output of headers and body is done by the Slim::run entry point.
+
+        // The below is copied from Slim::render (slim/slim@2.6.3).
+        // Modified to use View::fetch + Response::write, instead of View::display.
+        $this->app->view->appendData($this->_templateVars);
+        $body = $this->app->view->fetch($this->_template);
+        $this->app->response->write($body);
     }
 
 }

src/Xhgui/Controller/Run.php

@@ -22,6 +22,13 @@ public function __construct(Slim $app, Xhgui_Searcher_Interface $searcher)
 
     public function index()
     {
+        $response = $this->app->response();
+        // The list changes whenever new profiles are recorded.
+        // Generally avoid caching, but allow re-use in browser's bfcache
+        // and by cache proxies for concurrent requests.
+        // https://github.com/perftools/xhgui/issues/261
+        $response->headers->set('Cache-Control', 'public, max-age=0');
+
         $request = $this->app->request();
 
         $search = array();
@@ -73,6 +80,16 @@ public function index()
 
     public function view()
     {
+        $response = $this->app->response();
+        // Permalink views to a specific run are meant to be public and immutable.
+        // But limit the cache to only a short period of time (enough to allow
+        // handling of abuse or other stampedes). This way we don't have to
+        // deal with any kind of purging system for when profiles are deleted,
+        // or for after XHGui itself is upgraded and static assets may be
+        // incompatible etc.
+        // https://github.com/perftools/xhgui/issues/261
+        $response->headers->set('Cache-Control', 'public, max-age=60, must-revalidate');
+
         $request = $this->app->request();
         $detailCount = $this->app->config('detail.count');
         $result = $this->searcher->get($request->get('id'));